[SRE, NF-kappaB, and AP-1 DNA-binding activities induced by A431 cell adhesion correlate with actin cytoskeleton reorganization].

Cell adhesion to extracellular matrix proteins induces activation of different signal molecules and influences gene expression. As shown earlier, epidermoid carcinoma A431 cell adhesion to fibronectin, laminin-2/4 or antibodies to receptor EGF (ab EGFR) results in reorganization of specific cell shape and actin cytoskeleton in the majority of cells. This study resolves a question whether morphological changes are accompanied with some cell response at the level of gene expression in nuclei. We have shown that cell reattachment promotes a specific DNA-binding of nuclear extracts with consensus sequences SRE, NF-kappaB and AP-1, compared to the control. NF-kappaB and AP-1 activities were considerably reduced in spread cells, which did not show actin filament's structures typical for the ligands. SRE specific proteins demonstrated other peculiarities and depended on the type of immobilized ligands. Our results argue that actin cytoskeleton reorganization, induced by cell adhesion to immobilized ligands at the early period after cell reattachment, is correlated with a specific answer at the levels of DNA-binding activity of transcription factors SRE, NF-kappaB and AP-1.